Possible causes for engine pinging/knocking
* too-lean fuel/air mixture (not enough gas for the air present) - Clogged Fuel Filter/Injectors/Lines
* incorrect valve timing - Possible
* engine cooling system inadequacy - I doubt this very much!
* high intake-air temperature - Intake manifold is plastic, and is situated at the front of the car, and would be a lot colder than other cars. Remove the air filter restrictor to let the engine breath properly.
* driving in too high a gear - Come on! Drive properly.
* excessive carbon deposits - Drive the car a little harder
* poor combustion chamber design/shape - If this was the case, the Mazda 3 would also be experiencing this same problem, Go Volvo!
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